#习题4：变量（variable）和命名
cars = 100; #汽车数100
space_in_a_car = 4.0; #汽车容量
drivers = 30; #司机30人
passengers = 90;#乘客90人
cars_not_driven = cars - drivers;#没有司机的汽车
cars_driven = drivers;#汽车司机
carpool_capacity = cars_driven * space_in_a_car;#运载能力
average_passengers_per_car = passengers / cars_driven;#每车平均旅客数

print ("There are ",cars,"cars available.");#有多少有效车辆
print ("There are only ",drivers,"drivers available." );#有多少有效司机
print ("There will be ",cars_not_driven,"empty cars today.");#有多少没司机的车
print ("We can transport ",carpool_capacity,"people today.")#今天的运载能力
print ("We have ",passengers,"to carpool today.")#今天有多少人用车
print ("We need to put adout ",average_passengers_per_car,"in each car.")


